Exchange is setup in in a subfolder of the webroot (c:\inetpub\webroot\ ) so exchange normally loads a login prompt at
http://xyz.com/exchange/ but
http://xyz.com/ loads a page that says under construciton.

As far as the WAN / LAN, I'm just trying to basically say using IIRF and not using IIRF (LAN being direct access to the server and outside the LAN being over the WAN)